1. Field of the Invention
The present invention relates to image formation process and apparatus generally, and, more particularly, to image formation process and apparatus for enhancing the image quality of images printed on thicker, albeit narrower paper while employing an electrophotographic developing technique.
2. Description of the Related Art
In general, an image forming apparatus that employs an electrophotographic developing technique such as a facsimile, a printer and a complex machine, is equipped with an electrification roller, a photosensitive drum, a transfer roller, a developing roller, a toner supply roller, a fixer and a laser scanning unit (i.e., a “LSU”) for printing images onto a printable media such as a cut sheet of paper. I have noticed deficiencies in the pre-transfer system of image forming processes and apparatus. By way of example, if the user intends to form an image on a printable material that is relatively thicker than the standard grade of xerographic paper such as an envelope, the toner coated on the photosensitive drum is not transferred onto the paper and the remaining toner on the photosensitive drum is transferred onto the next piece of printable material that passes along the path conveying the printable material through the apparatus, thereby causing a mis-transfer which is referred to as “ghost phenomenon”, because the transfer electric field cannot transmit the thick paper. Moreover, when a thick envelope having a relatively narrower width in comparison to a sheet of A4 or 8½″ by 11″ paper is used in a transfer system using a conductive roller, in a state wherein a high voltage required for the transfer is applied to the transfer roller, the conductive layer of the photosensitive drum is broken. This defect is frequently referred to as a “pin hole”, and occurs in the region (either on the right, the left, or possibly on both sides of the sheet of the printable media) where the transfer roller and the photosensitive drum come into direct contact with each other due to the absence of any intermediate printable media, thereby causing fatal and unrepairable damage to the photosensitive exterior circumferential surface of the drum.